Cryogenic Hydrogen Transfer via Dual-Stage Compression
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Solution Overview
Problem
Existing cryogenic hydrogen compression processes are inefficient due to pressure differentials and pressure variations in the initial storage tank, which affect the efficiency of hydrogen transfer from a liquid state to a gaseous state at high pressures.
Innovation Solution
A process involving separate first and second compression means, where the operating frequency of the first compression means is controlled to maintain hydrogen in a supercritical state during the first pumping step, thereby stabilizing the hydrogen and optimizing the second pumping step for efficient transfer to a final state at pressures greater than or equal to 500 bar.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If two compression stages are used to bring hydrogen to supercritical state, then transfer efficiency is improved, but device complexity increases due to dual compressors and common drive mechanism
Solution Approach 1:
The compression process is divided into two independent stages with separate compressors (first compressor for initial compression to intermediate pressure, second compressor for final compression to high pressure). This segmentation allows each compressor to be optimized for its specific pressure range, improving overall transfer efficiency while maintaining manageable system complexity through modular design.
Solution Approach 2:
The operating frequencies of the two compressors are made independent and controllable, allowing dynamic adjustment of each compressor's operation based on real-time system conditions. This enables optimization of the compression process efficiency while providing flexibility to manage device complexity through adaptive control rather than fixed mechanical coupling.
2Stress or pressure
If compression means are designed to withstand high compression forces, then final pressure requirement is met, but pressure differential constraints increase device complexity
Solution Approach 1:
The total pressure differential (from initial to final pressure) is segmented into two manageable stages: first compressor handles the initial compression to intermediate pressure, and second compressor handles the final compression to high pressure. This reduces the pressure differential constraint on each individual compressor, simplifying the mechanical design requirements for each unit.
Solution Approach 2:
An intermediate pressure stage is introduced as a mediator between the initial low pressure and final high pressure states. The first compressor brings hydrogen to this intermediate supercritical state, which then serves as the input for the second compressor. This intermediary state reduces the compression force constraints on each compressor by avoiding the need for a single compressor to handle the entire pressure differential.
3Productivity
If initial storage tank pressure varies, then hydrogen transfer efficiency is impacted, but control complexity increases when attempting to stabilize pressure
Solution Approach 1:
The operating frequency of the first compressor is controlled based on feedback from pressure sensors monitoring the intermediate state. This feedback control stabilizes the intermediate pressure, ensuring consistent conditions for the second compressor and maintaining high transfer efficiency without requiring complex active pressure regulation systems.
Solution Approach 2:
Instead of actively controlling the initial storage tank pressure, the system accepts pressure variations and compensates by adjusting the operating parameters (frequency) of the compressors. This parameter change approach maintains transfer efficiency while avoiding the complexity of active pressure stabilization systems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This process enhances the efficiency of hydrogen transfer by maintaining hydrogen in a supercritical state, reducing the need for decompression and stabilizing the operation of the second compression means, thus achieving superior efficiency compared to prior art methods.
Implementation Method 1
a first step of pumping the hydrogen from the initial state thereof to an intermediate state wherein the hydrogen has a pressure greater than that of the initial state thereof
Implementation Method 2
a second step of pumping the hydrogen from the intermediate state thereof to the final state thereof
Implementation Method 3
the first compression means and the second compression means each operate at an operating frequency, the operating frequencies being independent from one another, the operating frequency of the first compression means being controlled according to the hydrogen pressure at the end of the first pumping step to keep it within a pressure range at the end of the first pumping step corresponding to supercritical conditions
Data Source
AI summary
A process for transferring hydrogen from a first tank wherein the hydrogen is in an initial liquid state at a pressure of the order of 10 bar to a second tank wherein the hydrogen is in a final state at a pressure greater than or equal to 500 bar. The process includes: a first pumping step of the hydrogen from the initial state thereof to an intermediate state wherein the hydrogen has a pressure greater than that of the initial state thereof; and a second pumping step of the hydrogen from the intermediate state thereof to bring it to the final state thereof. The first pumping step and the second pumping step are carried out respectively by mutually separate first compression and second compression elements.